Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -4308,10 +4308,13 @@
     while( pWInfo->pLoops ){
       WhereLoop *p = pWInfo->pLoops;
       pWInfo->pLoops = p->pNextLoop;
       whereLoopDelete(db, p);
     }
+    if( pWInfo->bShortcut ){
+      whereLoopClear(db, pWInfo->a[0].pWLoop);
+    }
     sqlite3DbFree(db, pWInfo);
   }
 }
 
 /*
@@ -5558,11 +5561,10 @@
   u8 priorJoinType = 0;
   WhereLoop *pNew;
 
   /* Loop over the tables in the join, from left to right */
   pNew = pBuilder->pNew;
-  whereLoopInit(pNew);
   for(iTab=0, pItem=pTabList->a; iTab<nTabList; iTab++, pItem++){
     pNew->iTab = iTab;
     pNew->maskSelf = getMask(&pWInfo->sMaskSet, pItem->iCursor);
     if( ((pItem->jointype|priorJoinType) & (JT_LEFT|JT_CROSS))!=0 ){
       mExtra = mPrior;
@@ -6274,11 +6276,11 @@
 **
 ** Return non-zero on success, if this query can be handled by this
 ** no-frills query planner.  Return zero if this query needs the 
 ** general-purpose query planner.
 */
-static int whereShortCut(WhereLoopBuilder *pBuilder){
+static int whereShortCut(sqlite3 *db, WhereLoopBuilder *pBuilder){
   WhereInfo *pWInfo;
   struct SrcList_item *pItem;
   WhereClause *pWC;
   WhereTerm *pTerm;
   WhereLoop *pLoop;
@@ -6309,15 +6311,18 @@
     pLoop->rRun = 33;  /* 33==sqlite3LogEst(10) */
   }else{
     for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
       u32 mask = WO_EQ;
       assert( pLoop->aLTermSpace==pLoop->aLTerm );
+      if( HasRowid(pTab)==0 && IsPrimaryKeyIndex(pIdx) ){
+        mask |= WO_IS;
+        if( whereLoopResize(db, pLoop, pIdx->nKeyCol) ) return 1;
+      }else
       if( !IsUniqueIndex(pIdx)
        || pIdx->pPartIdxWhere!=0 
        || pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace) 
       ) continue;
-      if( HasRowid(pTab)==0 && IsPrimaryKeyIndex(pIdx) ) mask |= WO_IS;
       for(j=0; j<pIdx->nKeyCol; j++){
         pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 0, mask, pIdx);
         if( pTerm==0 ) break;
         pLoop->aLTerm[j] = pTerm;
       }
@@ -6345,10 +6350,11 @@
       pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
     }
 #ifdef SQLITE_DEBUG
     pLoop->cId = '0';
 #endif
+    pWInfo->bShortcut = 1;
     return 1;
   }
   return 0;
 }
 
@@ -6615,11 +6621,11 @@
       whereTermPrint(&sWLB.pWC->a[i], i);
     }
   }
 #endif
 
-  if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
+  if( nTabList!=1 || whereShortCut(db, &sWLB)==0 ){
     rc = whereLoopAddAll(&sWLB);
     if( rc ) goto whereBeginError;
   
     /* Display all of the WhereLoop objects if wheretrace is enabled */
 #ifdef WHERETRACE_ENABLED /* !=0 */

Index: src/whereInt.h
==================================================================
--- src/whereInt.h
+++ src/whereInt.h
@@ -410,10 +410,11 @@
   u8 sorted;                /* True if really sorted (not just grouped) */
   u8 okOnePass;             /* Ok to use one-pass algorithm for UPDATE/DELETE */
   u8 untestedTerms;         /* Not all WHERE terms resolved by outer loop */
   u8 eDistinct;             /* One of the WHERE_DISTINCT_* values below */
   u8 nLevel;                /* Number of nested loop */
+  u8 bShortcut;             /* Plan generated by whereShortCut() */
   int iTop;                 /* The very beginning of the WHERE loop */
   int iContinue;            /* Jump here to continue with next record */
   int iBreak;               /* Jump here to break out of the loop */
   int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
   int aiCurOnePass[2];      /* OP_OpenWrite cursors for the ONEPASS opt */

Index: test/whereK.test
==================================================================
--- test/whereK.test
+++ test/whereK.test
@@ -55,9 +55,23 @@
 do_execsql_test 1.4.1 { SELECT v FROM t1 WHERE w IS 3   AND x = 3 } {C}
 do_execsql_test 1.4.2 { SELECT v FROM t1 WHERE w = '4' AND x IS 4 } {d}
 
 do_eqp_test 1.5.1 { SELECT b FROM t3 WHERE a IS ? } {/SCAN TABLE/}
 do_eqp_test 1.5.2 { SELECT b FROM t3 WHERE a = ? } {/SEARCH TABLE/}
+
+#-------------------------------------------------------------------------
+# Check that this works with PRIMARY KEY indexes that have large numbers
+# of columns.
+
+do_execsql_test 2.1.1 {
+  CREATE TABLE x1(a, b, c, d, e, f, g, h, i,
+    PRIMARY KEY(a, b, c, d, e, f, g)
+  ) WITHOUT ROWID;
+}
+do_eqp_test 2.1.2 { 
+  SELECT i FROM x1 WHERE 
+  a IS ? AND b IS ? AND c IS ? AND d IS ? AND e IS ? AND f IS ? AND g IS ?
+} {/SEARCH TABLE/}
 
 finish_test